numpy.asarray

numpy.asarray(a, dtype=None, order=None)

Convert the input to an array.

Parameters:

a : array_like

输入数据，可以转换为数组的任何形式。这包括列表、元组组成的列表、元组、元组组成的元组，列表组成的元组和ndarrays。

dtype : data-type, optional

By default, the data-type is inferred from the input data.

order : {‘C’, ‘F’}, optional

使用以行为主（C风格）还是以列为主（Fortran风格）的内存表示。Defaults to ‘C’.

Returns:

out : ndarray

a的数组解释。No copy is performed if the input is already an ndarray. If a is a subclass of ndarray, a base class ndarray is returned.

另见

asanyarray

类似的函数，子类可以原样返回。

ascontiguousarray

Convert input to a contiguous array.

asfarray

Convert input to a floating point ndarray.

asfortranarray

Convert input to an ndarray with column-major memory order.

asarray_chkfinite

Similar function which checks input for NaNs and Infs.

fromiter

Create an array from an iterator.

fromfunction

Construct an array by executing a function on grid positions.

Examples

Convert a list into an array:

>>> a = [1, 2]
>>> np.asarray(a)
array([1, 2])

Existing arrays are not copied:

>>> a = np.array([1, 2])
>>> np.asarray(a) is a
True

If dtype is set, array is copied only if dtype does not match:

>>> a = np.array([1, 2], dtype=np.float32)
>>> np.asarray(a, dtype=np.float32) is a
True
>>> np.asarray(a, dtype=np.float64) is a
False

与asanyarray相反，ndarray的子类不会原样返回：

>>> issubclass(np.matrix, np.ndarray)
True
>>> a = np.matrix([[1, 2]])
>>> np.asarray(a) is a
False
>>> np.asanyarray(a) is a
True